Based on a financial advisory I read, people should spend no more then 10% of their monthly income on a car payment(s).

I think 10% of pre tax income is an absurdly high amount of money to spend on a car. Remember this is pre tax so if you look at it as percent of disposable income it is a lot more. Especially when you also net out mortgage payments, children's school fees, wife/girlfriend, etc.

I would advise spending no more than 2-3% of income on a car. Better to save and retire early. Driving a nice car is great, but not if it means working till old age. I'd rather retire by 50 than drive Bentleys and Ferraris.